duodenal atresia can be assoc w/ what genetic cause?
trisomy 21
difference btwn omphalocele and gastroschisis
gastroschisis - not covered by peritoneum
omphalocele - herniated through umbilical cord, still covered by peritoneum
MC tracheoesophageal embyrological anomaly
esophageal atresia w/ distal tracheoesophageal fistula
baby w/ palpable “olive mass” in epigastric region and nonbilious projectile vomiting @2wks age
congenital pyloric stenosis
GI structures that are retroperitoneal (5)
duodenum (2nd and 3rd stages) pancreas (except tail) colon (desc and asc) esophagus (lower 2/3) rectum (lower 2/3)
falciform ligagment arises from what embryo structure?
ligamentum teres (derivative of fetal umbilical vein)
where are Meissner’s and Auerbach’s plexi located in the gut wall?
Meissner’s - submucosal
Auerbach’s - myenteric > muscularis externa
plicae circularis / valves of Kerckring - what and where are they found
valvular flaps, most prominent in jejunum
peyer’s patches are mostly found where?
ileum
SMA syndrome
3rd segment of duodenum gets stuck between SMA and aorta > obstruction
which part of colon is most vulnerable to ischemia?
splenic flexure (watershed region)
3 branches of celiac trunk
common hepatic, splenic, left gastric
line where endoderm meets ectoderm in gut
pectinate (dentate) line
femoral canal contents
lateral to medial: NAVEL
nerve, artery, vein, empty space, lymphatics
Hesselbach’s triangle
inferior epigastric vessels, lateral border of rectus abdominis, inguinal ligament
site of direct inguinal hernias
direct vs indirect inguinal hernias
direct - through hesselbach’s triangle, only covered by external spermatic fascia in guys, medial to inf epigastric artery
indirect - into scrotum w/ spermatic cord, covered by all layers of spermatic fascia, lateral to inf epigastric artery
gastric inhibitory peptide
decreases gastric acid secretion and inc pancreatic insulin secretion in response to presence of glucose in duodenum
vasoactive intestinal polypeptide
inc intestinal water and electrolyte secretion, relaxation of intestinal smooth muscle and sphincters
secreted in response to vagal stimulation or distension, less when there is adrenergic stimulation
motilin
stimulates MMCs in intestines
secretion increased in fasting state
what cell makes gastric intrinsic factor?
parietal cell
Brunner’s glands
in duodenum, secrete bicarb to neutralize stomach acid
what are the ion changes to pancreatic secretions based on flow rate?
low flow > high Cl
high flow > high bicarb
how is pancreatic trypsinogen activated?
by enterokinsae/enteropeptidase secreted by duodenal mucosa
what transporter absorbs glucose in gut?
SGLT1 (Na dependent)
Peyer’s patches -what are they
unencapsulated lymphoid tissue with M cells that take up antigen and B cells which turn into IgA secreting plasma cells (give them protective secretory component)
rate limiting enzyme of bile synth
cholesterol 7alpha-hydroxylase
what is added to bile as part of conjugation?
glucuronic acid
MC tumor of salivary glands
pleomorphic adenoma - benign, made of cartilage and epithelium
Warthin’s tumor
benign cystic tumor w/ germinal centers in the salivary gland
MC malignant tumor of salivary gland
mucoepidermoid CA. mucinous and squamous components, painful b/c involved facial nerve
can get achalasia 2/2
chaga’s dz
cause of primary achalasia
loss of Auerbach’s/myenteric plexus
who tends to get non-iatrogenic Mallory Weiss tears?
alcoholics and bulimics
Plummer Vinson syndrome
triad of:
dysphagia (esophageal webs)
glossitis
iron deficiency anemia
tropical sprue
malabsorption w/ unk cause
responds to abx
similar to celiac
extraintestinal sx of whipple’s dz
cardiac sx, arthralgias, neuro sx
part of intestine most affected by celiac
distal duodenum or proximal jejunum
abetalipoproteinemia
dec apolipoprotein B > can’t make chylomicrons > fat accumulation in enterocytes > malabsorption + neuro manifestations
HLAs assoc w/ celiac
DQ2 and DQ8
Curling’s ulcer
in burn pts, dec plasma volume > sloughing off of gastric mucosa > ulcer
Cushing’s ulcer
in brain injury pts
inc vagal stimulation > inc ACh > inc acid secretion > ulcer
Menetrier’s disease
gastric hypertrophy w/ protein loss, parietal cell atrophy, and inc mucous cells. precancerous. rugae look like brain gyri they are so hypertrophied
Virchow’s node
stomach cancer involvement of left supraclavicular node
Krukenberg’s tumor
bilateral metastases of stomach cancer to the ovaries
Sister Mary Joseph’s nodule
subQ periumbilical metastasis of stomach cancer
Crohn’s vs Ulcerative Colitis - where and what type of lesions
Crohn’s - skip lesions including both small and large bowel. Cobblestone mucosa (transmural involvement), noncaseating granulomas, bowel wall thickening, linear ulcers and puched out aphtae
UC - always rectal invovlement going proximally. Mucosa/submucosa only. Friable pseudopolyps, loss of haustra, more bleeding than in Crohn’s
Zenker’s diverticulum
false diverticulum of esophageal mucosa through Killian’s triangle (btwn thyropharyngeal and cricopharyngeal parts of inf pharyngeal constrictor)
sx: halitosis, dysphagia, obstruction
Meckel’s diverticulum
persistance of vitelline duct
has 2 types of epithelia - gastric and pancreatic
MC congenital anomaly of GI tract
Meckel’s diverticulum
Hirschsprung’s disease
congenital megacolon due to lack of ganglion cells / enteric nervous system in part of colon due to lack of neural crest migration.
presents as chronic constipation early in life
MCC small bowel obstruction
adhesions
which type of colon adenamous polyp is more likely to turn into cancer - tubular or villous?
villous
Peutz Jeghers syndrome
AD
multiple nonmalignant hamartomas in GI tract. Hyperpigmented mouth, lips, hands, genitalia. Assoc w/ inc risk of CRC and other visceral malignancies
familial adenomatous polyposis - type of inheritance and what is mutated
AD
APC gene
Gardner’s syndrome
FAP + osseous and soft tissue tumors, congenital hypertrophy of RPE
Turcot’s syndrome
FAP + malignant CNS tumor
Lynch Syndrome / HNPCC - inheritance and what is wrong w/ genes
AD
DNA mismatch repair genes mutated
bacteria assoc w/ colon cancer
strep bovis
series of mutations that lead to colon cancer
loss of APC > K-RAS mutation > loss of p53
carcinoid tumor
neuroendocrine tumor in appendix, ileum, or rectum. most common malignancy of small intestine. produces 5-HT, which is processed by liver unless it has metastasized beyond portal circulation > carcinoid syndrome (wheezing, right heart mumur, diarrhea, flushing)
Reye’s syndrome
childhood hepatoencephalopathy when child w/ viral illness gets aspirin. Findings: mitochondrial abnlmalities, fatty liver, hypoglycemia, vomiting, hepatomegaly, coma, often fatal
Mallory bodies
intracytoplasmic eosinophilic inclusions seen in alcoholic hepatitis
marker for hepatocellular carcinoma
alpha fetoprotein
hepatic adenoma
benign liver tumor, assoc w/ OCP or steroid use
nutmeg liver caused by
congestion in liver due to RHF or Budd Chiari syndrome
Budd Chiari syndrome
occlusion of IVC or hepatic vein w/ centrilobular congestion and necrosis > congestive hepatopathy
alpha 1 antitrypsin def - inheritance and 2 main manifestations
codominant
cirrhosis or panacinar emphysema
Gilbert’s syndrome
mild dec in UDP-glucuronyl transferase, asymptomatic / benign. mild inc in unconjugated bilirubin
Crigler Najjar syndrome
absence (type 1) or significant dec (type 2) of UDP glucuronyl transferase. High levels of bilirubin. Type 1 presents early and results in death in a few years. Type 2 can be treated w/ phenobarbital
Dubin-Johnson syndrome and Rotor’s syndrome
conjugated hyperbilirubinemia due to defective hepatic excretion. Black liver in Dubin Johnson, milder in Rotor’s. Benign/asymptomatic
other name for Wilson’s dz
hepatolenticular degeneration
tx of Wilson’s dz
penicillamine
Wilson’s dz gene
ATP7B gene
sx of Wilson’s disease
cirrhosis, corneal deposits (Kayser Fleischer rings), HCC, hemolytic anemia, basal ganglia degen > parkinsonian, asterixis, dementia/dyskinesia/dysarthria
classic triad of hemochromatosis
micronodular cirrhosis, DM, skin pigmentation
gene assoc w/ hemochromatosis
HFE gene
primary biliary cirrhosis more specific lab test
anti mitochondrial antibodies usually pos
primary sclerosing cholangitis - most cases assoc w/
ulcerative colitis
black vs brown pigmented gallstones - etiology
black - hemolysis, brown - infection
Charcot’s triad
for acute cholangitis
fever, RUQ pain, jaundice
Murphy’s sign
inspiratory arrest on deep RUQ palpation due to pain. assoc w/ biliary dz (esp gallstones)
marker for pancreatic CA
CA19-9
which H2 blocker has lots of SEs? what are they?
cimetidine inhib cytP450 (interactions), antiandrogenic effects, confusion/dizziness/HA, dec renal excretion of creatinine
sucralfate
binds to ulcer base to speed healing
side effect of misoprostol
diarrhea (can be severe)
octreotide - mech, uses, SEs
somatostatin analog
stop variceal bleeds, acromegaly, VIPoma, carcinoid tumors
nausea, cramps, steattorrhea (basically impaired digestion)
electrolyte abnlmality that can be caused by all antacids
hypokalemia
lactulose - 2 uses
osmotic laxative and treats hepatic encephalopathy - bacteria break it down into lactic and acetic acid which promote nitrogen excretion
infliximab is anti-
TNF
sufasalazine - class and what its used for
salicylates used for IBD
ondansetron mech
5HT antagonist - potent antiemetic
metoclopramide - mech, use, SE
D2 receptor antagonist -inc GI tone, motility
used for diabetic and post op gastroparesis, antiemetic
SE - parkinsonian effects, depression, restlessness, drowsiness, fatigue, nausea, diarrhea